I cleaned and kept 2-3 bagged heads per variety, except for about 10 varieties I only had one bag. I sent in around 5000 seed each of 50 varieties to FTT seed bank and to another member that is keeping a back up of all the varieties. I still have plenty for swapping. It was one hell of a job. I'm cutting back to about 5 varieties this year and will concentrate on strictly leaf.
I went to a rattlesnake roundup in in Cisco, Texas in 1958. (I was a young boy.) The Humane Society was there telling them how to humanely kill them. But I always thought your method was best or whatever's handy.